Acta endocrinologica
-
Acta endocrinologica · Aug 1975
The sequence of pituitary responses to synthetic luteinizing hormone releasing hormone (LH-RH) throughout the normal menstrual cycle.
Thirty-one ovulatory women between 20 and 33 years of age were given 150 mug of synthetic LH-RH during different phases of the menstrual cycle. Five patients were studied during the early follicular phase (days 4-7); 10 patients during the late follicular phase (days 9-12); 6 patients during the "LH Surge"; 5 patients during the early luteal phase (days 14-16); 3 patients during mid-luteal phase (days 17-21); and 2 patients during late luteal phase (days 22-27). Oestrogen, progesterone, FSH and LH levels were determined from 30 min prior to LH-RH administration to 90 min thereafter in all cases. ⋯ Maximum pituitary responsiveness appears to occur in a gonadal steroid milieu of high oestrogen levels in association with rising but low progesterone levels. Progesterone or a crucial oestrogen: progesterone ratio may in fact potentiate pituitary release of LH during the early stages of corpus luteum formation. Pituitary responsiveness to LH-RH correlates positively with basal LH and oestrogen levels during the menstrual cycle and with the oestrogen:progesterone ratio during the luteal phase.